Tape on Tape

After my morning ride today, I noticed that the bar tape on Purple Haze had come loose.

This tends to happen after a few years when the electrical tape that wraps the end goes a bit gummy and starts sliding around. Luckily the fix is easy, and starts with removing the old electrical tape.

And cleaning up some of the gunk underneath, of course.

Then I can rewrap it in its usual orderly manner and finish the end with some fresh electrical tape.

In this case I switched things up and went for some white electrical tape to match the bar tape a bit better. Of course that meant I had to replace the tape on the other side too.

And of course now that this fresh white electrical tape is sitting next to my not-so-fresh white bar tape, this would be a good time to give it a little cleaning.

Well, it's better but it's not perfect, and this is life with white bar tape: it's only ever white once.

You Can't Tuna Fish

When we last left off with the Rat Shack Synth, it was making noise but not very well. The tone was drifting upwards on the main oscillators and oscillator 1 wasn't tracking the keyboard properly.

But thankfully every problem has a solution, and after a bit of head scratching I managed to get everything working perfectly.

Frequency Modulation

This right here is a Yamaha Reface DX. It's modelled after their classic line of Digital FM synths from the 80s and 90s, with the DX7 being perhaps the most famous and widely used synth.

This one has a problem, though. Some of the front panel switches don't work, and some of the LEDs don't light up.

For example, here's the LED behind the FREQ button lighting up as it should:

And here's the LED behind the LEVEL button doing a whole lot of nothing:

Oh and also it doesn't make any sound. I guess that's important too.

Now one of the problems with these compact synths is that because of their small size, people often tend to treat them like those old toy synths, even though, well...

But thankfully I didn't have to pay $500 for this one. Anyway, let's crack it open and see what's inside.

And interestingly there's more in here than I thought there might be. These days you can run a synth like this on a board the size of your thumbnail (not the chip, but the whole board) but I guess the Yamaha engineers decided to fill the space available to them. No harm done I suppose.

So over here on the left side is the chip that drives the switch and LED matrix.

If we probe one of the matrix lines with the scope, we can see it scanning.

But if we probe another line next to it, we see something that looks almost like a flat line...

However, if we bring up the vertical scale a bit.

We can see that it's still trying to strobe the lines, but it's lost its pull-down resistor.

Now I could dig into this board and try to figure out which resistor is faulty, or trace down a broken via, but I really don't feel like it when replacement mainboards are still readily available.

Though at $150 they're not especially cheap, but given the bargain I got on the synth I'm still coming in under budget.

Now to get to the mainboard we have to remove the keys.

And the keybed PCB.

And then to get the mainboard out we of course need a different size screwdriver.

But once we've got those screws removed, the mainboard just lifts right out.

And then the new mainboard goes in, after we've removed the curious bits of kapton tape that were stuck to each connector.

And we can verify that the switches are working and the previously "dead" LEDs have come back to life.

But the synth still isn't making noise, curiously, so let's check the volume slider.

If we measure the resistance on the wiper for the octave slider next to it, we get a reasonable reading:

But unfortunately the volume slider is being rather unreasonable.

And after spraying it with a little contact cleaner...

It's somehow still not working. Lovely.

Just to test things out, let's try jumpering the volume slider with a fixed resistance.

And if we test the resistance now, we see a much different result.

But unfortunately the synth still doesn't make noise. Because I put the resistor on the wrong pin, it should have been like this.

And now the synth makes sound. Good. So we can order up a volume pot, and let's just go ahead and replace the octave pot too since it was reading a bit funny on one end.

We just have to pull out this front panel sub-board.

And do a bit of desoldering. Using a hot air gun can really help with larger mechanical solder joints like these two tabs in the middle.

And with a little magical slurp from my solder sucker, both pots come out easily.

Goodbye old slider pots, you left us too soon.

Then the new pots get soldered in.

And all that's left to do is reassemble.

But there's still some finishing touches left.

Like replacing the missing rubber foot.

And getting rid of the Alkaline batteries before they leak and destroy everything.

And with all that done, we're back in business.

And ready to make some sweet 80s synth-pop!

A Roof Over My Head

So there's this piece of trim on the side of my roof that really could use some repainting.

The trouble is that it's behind this minefield here.

These are fiberglass roof panels. Seriously degraded fiberglass roof panels.

Basically if you touch this side, you die the itchy fiberglass death.

They didn't originally look this ugly, though, as evidenced by the part that was shaded under the overhang.

But that doesn't really help me much, so off they go.

I'm not sure if the panels were originally white and yellowed over time or if they were a yellow-cream colour from the start. The house was yellow when this awning was installed so the latter is certainly possible.

It was also stuck on with some weird yellow caulking where it met with the wall, which is a little pointless given that it's under an overhang so it's not like any water was ever going to get up there. At least it matched the old paint.

Speaking of colours, green was the trim colour when the house was yellow, and apparently they never bothered to repaint the awning frame. And, furthermore, never bothered to properly prime the aluminum so the paint would stick.

But the good news is I now have unimpeded access to the trim that needed painting, so I can start with a little bit of wire brushing to knock the loose paint off of it, as well as off of the awning frame.

And then a little love from the belt sander to level things out.

And finally we can get to the paint.

I used a rustoleum aluminum primer on the frame so we'll see how that works I guess. I'm pretty confident that the exterior white latex paint will stick just fine to the trim though, which is looking pretty fine.

Finally, a new set of roof panels goes on to replace those scrungy old ones.

These are a polycarbonate roof panel in the "white opal" colour, which is basically just translucent white. The good news at least is that there's no fiberglass in them to eventually be eroded to the surface, and they promise to be UV-protected though we'll see how that holds up because there's an awful lot of UV around here.